Remove unused API.

dart/sdk/lib/_internal/compiler/implementation/js/nodes.dart

Index: dart/sdk/lib/_internal/compiler/implementation/js/nodes.dart
diff --git a/dart/sdk/lib/_internal/compiler/implementation/js/nodes.dart b/dart/sdk/lib/_internal/compiler/implementation/js/nodes.dart
index afc27dec1cdf8bc4dd560d9748bb45814538936e..e6268a3053b4c4a2270286247c22d0b9ea2e69ee 100644
--- a/dart/sdk/lib/_internal/compiler/implementation/js/nodes.dart
+++ b/dart/sdk/lib/_internal/compiler/implementation/js/nodes.dart
@@ -481,12 +481,6 @@ abstract class Expression extends Node {
     return callWith(arguments);
   }
 
-  Expression equals(expression) => binary('==', expression);
-
-  Expression strictEquals(expression) => binary('===', expression);
-
-  Expression notEquals(expression) => binary('!=', expression);
-
   Expression operator +(expression) => binary('+', expression);
 
   Expression operator -(expression) => binary('-', expression);
@@ -503,10 +497,6 @@ abstract class Expression extends Node {
     return new Binary(operator, this, js.toExpression(expression));
   }
 
-  Expression assign(expression) {
-    return new Assignment(this, js.toExpression(expression));
-  }
-
   Expression update(String operator, expression) {
     return new Assignment.compound(this, operator, js.toExpression(expression));
   }